When three solar quotes land in your inbox and each one looks completely different, the temptation is to pick the cheapest. That is often the wrong choice. Understanding what each line item actually represents — and what it should cost — gives you the confidence to choose on value, not just price.
The Core Components of Every Quote
1. Solar Panels
This line should specify the panel brand, model, wattage, quantity, and total kWp. A quote that says only "6 kW solar panels" without naming a brand is a red flag. Verify the model against the manufacturer's specification sheet. Check the product warranty (typically 10–15 years) and the performance warranty (typically 25–30 years at a guaranteed degradation rate).
2026 benchmark pricing: €0.20–€0.40 per watt for the panels themselves, depending on tier and technology (PERC vs TOPCon vs HJT).
2. Inverter
The inverter is listed separately. You should see the brand, model, and rated output in kW. For hybrid systems, confirm the battery compatibility and the maximum battery voltage. Compare the inverter's efficiency rating (98%+ is standard for quality units from SMA, Fronius, SolarEdge, Sungrow).
Watch out for: Inverters sized smaller than your panel array kWp. A 5 kW inverter for a 6.5 kW panel array is sometimes intentional (clipping strategy) but should be explained.
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3. Mounting System / Racking
This covers the aluminium rails, clamps, and roof hooks that secure panels to your roof. The mounting system also defines wind and snow load compliance. In cyclone-prone or high-wind regions, do not accept a generic bracket — ask for the wind load engineering certificate.
Typical cost: 5–10% of total quote value.
4. Battery Storage (if included)
Should list the brand (BYD, Tesla Powerwall, Pylontech, Sonnen, GivEnergy), model, usable capacity in kWh, round-trip efficiency, and cycle life at 80% capacity retention. The usable capacity matters more than the nameplate — a 10 kWh battery with 90% usable delivers 9 kWh; one with 80% usable delivers 8 kWh.
5. Electrical Balance of System
This covers DC cabling, AC cabling, isolators, circuit breakers, and the main switchboard upgrade if needed. It is often bundled as a single line. Ask your installer to separate the switchboard upgrade cost if one is required — it can be €500–€1,500 and is sometimes used to inflate quotes artificially.
6. Monitoring System
Most inverters include cloud monitoring via their own platform. Some quotes add a third-party energy monitor (e.g., a CT clamp for whole-home consumption monitoring). This is usually worthwhile — you cannot see your self-consumption ratio without it.
7. Labour and Installation
Labour is typically 15–25% of the total quote. It covers roof penetration, mounting, wiring, inverter commissioning, and handover. Two quotes with identical equipment but a €1,500 labour gap may reflect very different installation quality — or one installer simply paying their electricians properly.
8. Permits and Grid Connection
In most markets, solar installations require a grid connection application and often a building permit. These fees should appear explicitly in the quote. If they are absent, ask whether they are included or who pays for them. Grid connection applications can cost €100–€500 depending on jurisdiction.
9. Warranties Offered
A compliant quote should state:
- Panel product warranty (10–15 years)
- Panel performance warranty (25–30 years)
- Inverter warranty (5–12 years, extendable)
- Workmanship/installation warranty (typically 2–10 years depending on country)
10. System Yield Estimate
The best quotes include an annual yield estimate in kWh/year, calculated using tools like PVGIS, PVWatts, or PVSol. Ask the installer what irradiance data source they used. If the yield estimate seems 15% higher than PVGIS suggests for your postcode, be sceptical.
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Comparison: What a Fair 2026 Quote Looks Like
| Component | Budget | Mid-Range | Premium |
|---|---|---|---|
| Panels (per Wp) | €0.18–0.22 | €0.25–0.32 | €0.35–0.45 |
| Inverter (5 kW) | €600–900 | €900–1,400 | €1,400–2,000 |
| Mounting | Included | Included | Engineered |
| Labour (6 kWp) | €800–1,200 | €1,200–1,800 | €1,800–2,500 |
| Monitoring | Basic | Consumption CT | Advanced portal |
| Total (6 kWp, no battery) | €5,000–7,000 | €7,000–9,500 | €9,500–13,000 |
Want real quotes using this framework? Request instant solar offers through Comparisun and compare line items from vetted installers side by side.